Slack adjuster



Jan. 23, 1940. A. G. KERsHAw Er AL sLAc'sK` ADJUSTER 2 Sheets-Sheet l H MC 1v ORL .WE MH. m EQH .O VRU n A ,UN .A WN RMV. A B e. WN AA Q Ww! m@ Patented 23, 1940 UNITED# stacxlamusrtn j i ,"Arthur;GreenwoodvKershavv'and Kenneth Howard Leech, London, England; -assignors, by

mesne' assignments-,Apto The Westinghouse Air Brake Company, Wilmerding,y Pa., l a corporation of Pennsylvania Application Ma i ich 26, icas;y serial No.. 198,252

In Great Britain May2`1fL-1937 aclaimsl- .(cl.- 1ste-i202)A This invention relates vto automatic slack ad'- justing devices for braking apparatus ,o the well known kind in which the slack in the brake rig' ging is arranged Vto be adjusted' automatically, so as to maintain the slack substantially con' stant under all conditions, by means of screw and nut mechanism adapted to 'be operated during av stage of movement of the brakeV rigging through the intermediary of a suitable unidirectional clutch device by an operating arml adapted' to bemoved relatively to the slack adjusting' de.- 4

dle or lever may be associated with the uni-'.

directional clutch device, thisfcam being adapted to be moved to one position by means of. thehandle or lever soy as to disengage the""u nidirecf tional clutch device for permitting 're-setting of the slack adjusting device, and to be'moved vto another position so as to permit theuni-directional clutch device to be reenga'ged for further automatic adjustment after `the slack adjusting device has been re-set. l l

In the event of the uni-directional clutch device being left invits disengagedfcondition after re-setting has ybeen `eiected, or should the manually operable arrangements be 1 accidentally moved to the position in whichy theclutch is disengaged, the slack adjusting devicer would as be evident be inoperative. o i y According to the principal feature of `the-pres ent invention, however, in order-to avoid this disadvantage, the 1mi-directional clutchA rdevice is arrangedv to be reengaged automaticallyvasla result of the movement-of thejslack adjusting device or apart thereof in effecting an .application of. the-brakes. i. f Y

For example, the handle Orl-leven ofthe manu#- ally operable ,clutch disengaging arrangements may be arranged to project, when the clutchfis disengaged, into the path traversedin applying the 4brakesby the operating arm fof -the slack adjustingdevice or a member secured theretol and be arranged to be engagedbythe operating armvr -or 4member secured ,theretov andfgtnovejd`V by ,L this arm orinember in applying the brakes to its clutch/engaged position.

Iniiorder that the invention may .i be `lreadily understood it will now be described, by way of example` withl referenceto the accompanying drawingsasfapplied to a slack adjusting vdevice 'more particularly suitable for Vuid lpressure braking apparatus on railway" and`-v the 4ylike vehicles. i

In theaccompanying drawings 'Figure 1 is 'a' view of theslack adjusting device mainly vin vertical centrali"longitudinaly section; Fige`2 is a plan view of the device from below;V Figures 3 to 5 juste'r device; and vEigure `,Kaplan view of Va further detail of theslack adjuster device.

- arevsectionial views of details "ofthev` slack ad# l'teierring now in detail to the drawings, the i slack Aadjusting device corm'irises a fscrew fthraded rod ljkenlosed in a tubular sleeve 2 and -co-'o'perating lwith a correspondingly* screwthreaded nut 3 secured at its outer end 4 to the tubular sleeve 2 and" at its inner end V5 toa l 'tubular member t having an enlarged portion at its inner end formingan'annularshoulder rl.

'lhetubular vmember 6 `is'mounte'd 'in' a lbearing portion jof the hollow body 8a of the .slack Aadju sting'device rwhichis provided with an annular"`shoulder Q'vadapted to cooperate through 4the intermediary of a suitable packing ring 'Ill with `the yexternal shoulder 'l5Y` of the tubular n lefr'nber'. l

IThe outer y eind la of the screw-'threaded rod l is arranged to be coupled to theusual brake shoes through suitable rigging (not shown) and the hollow'fb'odyf 8aY `of 'the slack adjusting. device n i is provided with an eye portion H 'adapted to be connected, usuallythrough a lever or levers, (not shown) yto the Located within the hollow body 4liaof the device a lbearing sleeve l2 Ysuitablysupported at its opposite ends in' a` recess i3' inv the. shouldered Lsual braking cylinder piston rod,v

end of thetubularmember on theorie handv otherhandj Onthis bearing sleeve. l2 is rotatably' mounted a tubular driving ratchet member f" of the 'tubular member t. LA" tubular locking ratchet'member li8 is mounted'onvthefdriving' 1ratchet member |35 and has 'atoneend a y.number otratchet' teeth Al"9 Figure 5)*"similarwto y'those 'on' the drivingfratchetmember-t5 and iso-operatij lhavirig at one endfa' numberofinclined ratchet l teeth-i6 El) Akadapted 'to coloperatl'e with v,theinnergportions of correspondingloppositely in"- ing with the 'outer portions or the teeth n on' the shouldered end of the tubular member 6, suitable springs 26 and 2I being provided to urge the driving and the locking ratchet members respectivelyinto engagement with the shouldered end of the tubular member 6. 1

The driving ratchet member I5 is operatively coupled by means of splines 22 to a rockable lopoperating arm 23 may be coupled to one end of a bell-crank lever (not shown) carried by the brake cylinder piston cross-head` (not shown) by a suitable link (not shown), the other end of the lever being anchored to the brake cylinder or other suitable xed portion of the braking apparatus or vehicle, whereby said arm will be rocked A upon movement or" the brake cylinder piston, such arrangements however not forming part of. the

.-.gpresent invention and not being shown in'the drawings.

In operation, when a pull is exerted in the direction A (Figure 1) on the slack adjusting device by the movement of the brake cylinder piston the hollow body 9a. and with it the bear-l ing portion of the device is moved in the direction of the arrow A and carries with it, owing to the co-operation between the shoulders 1 and 9 referred to hereinbefore, the tubular member 1 6, the nut 3 and the screw-threaded rod I thereby applying the brakes. y

vDuring this movement the operating arm 23 isadapted to rotate the driving ratchet member I5 in such a direction that the teeth I6 on this 'f member slip over the inclined faces of the teeth I1 on the tubular member 6, the locking ratchet member I8 positively preventing the tubular.

member 6 from being rotated. In the event ofA the slack in the rigging exceeding a predeterf mined amount the driving-ratchet`member I5 will be rotated with respect to the tubular member 6 by an amount corresponding to the distance between two adjacent ratchet teeth and, when the brakes are being released and the operz' ating arm 23 being returned to its original position, the driving ratchet member I5 will rotate the tubular member 6 by an amount corresponding to the distance between two adjacent ratchet teeth. The rotation of the tubular member 6 is transmitted to Vthe nut 3 and the rotationof the latter with respect to the screw-threaded rod I will decrease the slack in the rigging by a corresponding amount.

As wear of the brake blocks occurs progressively the slack adjusting device operates progressively to take up more and `more slack,

` whilst the screw-threaded rod I gradually enters the tubular member 6 until eventually the nut 3 arrives at or near the outer end of the screw and no further automatic adjustmentis possible until the device is rep-set.

In order to provide a readily` visible indication as to the condition of the slack adjusting device at any time a disc or other member such-as 24 is secured or clampedfto tl'1eouter`r end of the y'is tubular sleeve 2 secured to the nut 3 and another disc or other member such as 25 is secured or clamped to the outer end la of the screwthreaded rod I. These'discs or indicating members 24 and 25 are so arranged that when ther device isre-set they are spaced apart at a distance corresponding or substantially equal to the maximum amount Aof slack capable of being taken up by the device between one re-setting and the next, so that as will be apparent the distance apart of the discs or other indicating members will give a ready indication of the operative condition ofthe slack adjusting device. When the4 twoA discs 'or indicating members 24' and 25 are observedv to be substantially in engagement with one another it will be apparent that resetting of the device is necessary. The disc or indicatingmember on the tubular sleeve 2 secured to the nut 3 may be provided with extended lugs or ears 24 to serve for the ready y rotation of the nut 3 in re-setting the device.

In order to permit the re-setting of the device a cam 26 having an operating handle or lever 21 is associated with the ratchet members I5 and I8, this cam 26 being adapted t0 be moved to one position by means of the handle or lever 21 so as to disengage the vratchet teeth I6 and I9 on'the members I5 and I8 from the ratchet teeth I1 on the tubular member 6 for permitting re-setting of the slack adjusting device and to be movedvto another position so as to permit the ratchet teeth I6 and I9 to be re-engaged with the ratchet teeth I1 for further automatic adjustment after the slack ladjusting device has been re-set.

The cam 26 comprises a substantially cylindrical memberhaving an operating stem 23 at its outer end and a out away portion 29 (Figure 6) at one'side of 'its inner end which permits the ratchet members I5 and I8 to be moved into engagement with the tubular member 6 by the action 0f the springs 20 and 2l when the cam 26 is rotated to the position in which it is shown in the drawings corresponding to the position of the handle or lever 21 indicated by full lines in Figure 2. The cam 26 is mountedin the body portion 8a, at the under side of the slack adjusting device, with its axis at right angles to the longitudinal axis of the device, and outside the bodyfportion 8a the stem 28 of thev cam' 26 is providedwiththe operating handle or lever 21. This handle or lever 21 has a projection 3D (Figure 2) which is arranged' toproject, when the ratchet'memb'ers are disengaged by movement of the lever 21't'o the position indicated by. dot and dash lines in Figure 2, into the path traversed in applying the brakes by a lug 3| on the operating arm 23 of the slack'adjusting device and is arranged to be engaged by the lug 3| so that the lever 2171s moved by this lugin applying the brakes to the position in full lines in Figure 2, in which the ratchet members are engaged;

Thus should the cam 26 be left inadvertently in the position'in which the ratchet members I 5 and Iaredisengaged from the ratchet teeth I1 of the tubular member 6, these members will automatically be re-engaged as a result of the movement of the operating arm 23 of the slack adjusting device in effecting the iirst subsequent vapplication of the brakes.

It will be evident that the invention is not limited to the particular construction and arrangement of the parts hereinbefore described by way of example which may be varied-,as desired to suit particular requirements Without exceeding the scope of the invention.

Having now described our invention, what We claim as new and desire to secure by Letters Paty ent, is:

operation thereof to take up slack, manually operative means for releasing said clutch device to render said take-up means operable independently of said clutch device, and actuating means operative automatically to effect operation of said manually operative means to render said clutch device eiective to operate said take-up means and to also effect operation of said clutchdevice to operate said take-up means.

2. A slack adjuster device for the brake'lrigging of a fluid pressure brake-system comprising slack take-up means, a clutch device operatively connected to said take-up means for eiecting the `operation thereof to take up slack, actuating means operative automatically to effect operation of said clutch device to operate said takeup means and a manually operative lever connected to said clutch device for releasing said clutch device to render said take-up means operable independently .of said clutch device, said actuating means being operative upon movement to operate said clutch device to ei'fectoperation of said lever to rendersaid clutch device effective to operate said take-up means.

3. A slack adjuster device for the brake rigging of a fluid pressure brake system comprising slack take-up means,'a clutch device operatively connected to said take-up means for effecting `the operation thereof to `take up slack, a movable member operative automatically to effect operation of said clutch device to operate said take-up means, and means including a manually operative lever` movable into the path traversed by said movable member in operating to take up slack, for releasing said clutch device to render said take-up means operable-independently of said 3 clutch device, said movable member being operative upon movement to take up slack to operate said lever to render said clutch device effective.

4. A slack adjuster device for the brake rigging of a iiud pressure brake system comprising slack take-up means, a driven ratchet member operative upon turning in one direction to effect the operation ci said take-up means to take up slack, a driving ratchet member cooperative with said driven member toeiect operation thereof, a third ratchet member secured against turning and cooperative with said driven member to hold said driven member against turning in the reverse direction, a rockable member connected to said driving member for effecting the operation thereof to turn said driven member, means operative to release said driving member and said third ratchet member from said driven member to render said driven member turnable in said reverse direction, and means operable by said rcckable member, upon movement to effect operation of said driving member, to operate said release means to effect cooperative engagement between said driven member member vand said third ratchet member.

5. A slack adjuster device for the brake rigging of a iluid pressure brake system comprising a slack take-up screw, a nut on said screw operative upon rotation in one direction on said screw to operate said :screw to take up Slack, ratchet means operatively connected to said nut for rotating said nut, a rockable member operative to effect operation of said ratchet means, means including a lever operative to effect operation of,y said ratchet means to release said nut for rotation in the opposite direction, and means operative by said member upon movement to effect operation of said ratchet means to operate said lever to condition'said ratchet means for rotating said nut. Y

ARTHUR GREENWOOD KERSHAW. KENNETH HOWARD LEECH.

and said driving 

